Certain known methods of grooming the snow covering of ski slopes is to flatten any mounds of snow using a blade fitted to the front of a crawler groomer; compact the snow covering using the groomer tracks; till a surface layer of the snow covering using a rotary tiller fitted to the rear of the groomer; and smooth the tilled snow covering using a mat mounted downstream from the rotary tiller, and which forms longitudinal furrows parallel to the travelling direction of the groomer.
The above steps can often be performed in different sequences, depending on the type of snow, temperature, ski slope gradient, etc., to achieve a snow covering of a given or designated particle size and density. One example of a groomer of the above type is described in European Patent No. 1,995,159.
The most energy-intensive grooming step is tilling the snow covering, especially when this is hard and icy.
As described in PCT Patent Application No. WO 2009/034184, PCT Patent Application No. WO 2009/034185, PCT Patent Application No. WO 2009/056576 and PCT Patent Application No. WO 2009/056578, the rotary tiller comprises a shaft rotated by a hydraulic or electric motor; and a number of teeth projecting from the shaft. The tiller is confined between the snow covering and a hood and, in use, the teeth on the tiller penetrate the snow covering and hurl clumps of snow against the hood to break up the clumps and form a hard surface layer on the snow covering of a given or designated particle size.
This known grooming method gives good results in terms of quality, but is highly energy-intensive.